This Might Hurt by Stephanie Wrobel

A story of sisters, secrets and a sanctuary with a dark heart from author of Sunday Times bestseller The Recovery of Rose Gold

Welcome to Wisewood. We'll keep your secrets, if you keep ours.
High-flier Natalie Collins always has a plan. Her younger sister Kit rarely does.

Until she finds Wisewood. When Kit joins the self-help retreat on a secluded Maine island, Natalie has concerns. Why does it forbid contact with the outside world? Is it a cult?

Then, after months of silence, she receives a message:

Would you like to come tell your sister what you did - or should we?

Who is digging into the Collins' past? Natalie will have to go to Wisewood to find out.

But it turns out Wisewood is far easier to get into than to leave...